Improvement in saw-grinding machines



UNITED STATES EEICE.

PATENT JOHN G. BAKER, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO HENRY DISS'ION, OF SAME PLACE.

IMPROVEMENT IN SAW-GRINDING MACHINES.

Specification forming part ofLctters Patent No. 53,725, dated April 3, 1866.

To all whom it may concern:

Be it knownthat I, JOHN G. BAKER, of Philadelphia, Pennsylvania., have invented an Improved Saw-Grinding Machine; and I do hereby declare the following to be a full, clear, and exact description of the same, reference being had to the accompanying drawing, and to the letters of reference marked thereon.

My invention consists of certain mechanism, fully described hereinafter, for grinding saw blades and reducing them to the desired taper.

In order to enable others skilled in the art to make and use my invention, Iwill now proceed to describe its construction and operation.

On reference to the accompanying drawings, which form a part of this specification, Fig ure l, Drawing No. l, is a side view of my improved saw-grindin g machine with one of the frames removed. Fig. 2 is a plan view of Fig. l. Fig. 3, Drawing No. 2, is a vertical section of part of the machine on the line l 2, Drawing No. I; Fig. 4, a transverse vertical section on the line 3 4, Fig. 2; Fig. 5, an inside view of the segment, showing the sawblade in its proper position; Fig. 6, an edge view of the same.

Similar letters refer to similar parts throughout the several views.

A and A' are the opposite side frames of the machine, and are connected together at suitable points by the cross-bars l a a. B is a driving-pulley secured to the shaft O, on which are two loose pulleys, B' and B2, one on each side ot' the pulley B, the said shaft C turning in the opposite frames of the machine. A belt'shifter, D,is arranged to slide in staples b on the oppositeside frames, and is furnished with the usual belt-guides. On the shaft O is a pinion, c, which gears into a cog-Wheel, E', on a shaft, E, the journals of which revolve in suitable boxes on the opposite side frames, A and A'. On this shaft E is a pulley, F, to which is secured one end of a belt, E", of gutta-percha or other suitable material, the other end of whiehis secured to the lower end of a segment, G, the latter being connected to a rock-shaft, H, by the four rods d l d d, and the center of this shaft coinciding with the center of the segment. One end of each of the rods d passes through a lug, e, there being one lug on each corner of ,the segment. (See Fig. 5.)

'Ihe segment G consists of aplate strengthened by the ribs g and the end pieces, g'. The saw-blade to be ground is placed against the concave face of the segment G and held securely in its position by the set-screws L and h', the latter being attached to a movable plate, i, which is held in position by the bell-crank lever i' one arm of which is acted on by a spring secured to the edge ot' the segment. The projecting ends of the set-screws h and Il' are beveled to correspond to a bevel made on each end of the saw, so that -however thin the lat-.

ter may be ground it cannot escape from the projecting ends ot' the set-screws.

On one side of the segment is cuta groove, j, (see Fig. 6,) adapted to the reception of adjustable dogs k, k', and k2, and to the dog k' is hinged an L-shaped catch, k3, the object of which will be rendered apparent hereinafter.

Passing through projections l l' on the inside'of the frame A' is a rod, I, having two projections, m and m', Fig. 5, the former of which is inserted into an opening in the beltshifter l), the end of the other arm, m', being so situated as to be in the range of the dogs 7u and L2.

A grindstone, J, is secured to a shaft, J', which turns and is permitted to have a limited end movement in boxes u and n', one end of this shaft having a driving-pulley, L, and on the other end a scroll cam-wheel, L, and a pulley, L', which can revolve together independently of the shaft. 'On the box N' is an arm, O, having a bent end, which projects into the groove ofthe scroll cam-wheel L. rIhe boxes n and a' are attached to slides on the opposite side frames of the machine, and have projections with interual screw-threads adapted to those on a shaft, N. Each of these screwshafts turn in a projection, q, on the frames, and each has a bevel-wheel, q', gearing into a similar wheel on a shaft, P, which is provided with a suitable hand-wheel, r, and which turns in projections on the ends of the side frames.

Q is a stone picker or dresser, consisting of a series of wheels, s, which have pointed teeth, and which are hung loosely upon a stationary spindle, Q', and are inclosed on a boX or casing situated at the rear of the grindstone. This spindle passes through guides S S, which are adjustable one on each frame of the machine, and one end of the spindle is provided with an appropriate handle, t, and is prevented from turning by a key in one. of the adjustable guides iitting into a groove on the spindle. These adjustable guides are connected to slides by screw-rods u,which are bolted to projections. u on the said slide lt, there being a nut on each side of the projection, so that the boxes S and slides R may be adjusted from and toward each other at pleasure. The screw shafts N pass through the said projections o, the latter having internal threads adapted to the threads of the shaft.

Operation: By pressing upon the long arm of the spring-lever i the projecting end of the set-screw h may be raised sufficiently to allow a saw-blade to be laid against the face of the segment, the lower beveled end of the screw being inserted beneath the beveled projecting end of the set-screw h. As soon as the sawblade is thus adjusted the pressure upon the lever i is withdrawn, the pin 7L is depressed by the spring, its beveled head fitting against the beveled end of the saw-blade, which is thus securely held between the two set-screws. rJ'Dwo driving-belts are used, one crossed and the other straight, in connection with the pnlleys B,B, and B2,the.se belts being guided by the projections on the shifter D. Supposing the straight driving-.belt to be turning the pulley B in the direction of its arrow, the belt E must be unwound from the pulley F, and consequent-ly the segment G must move downward by its own weight in the arc of a circle of which the shaft H is the center, the saw-blade being subjected to the action of the grindstone during this movement.

Then the adjustable dog 7c comes in contact with and moves the arm m on the rod I the arm m will so operate the belt-shifter as to transfer the straight belt onto a loose pulley and the crossed belt onto the fast pulley B; hence the motion of the shaft C must be reversed, and the segment mustcommence its u pward vibration until the plate k' strikes the arm m', when the position of the belt will be again reversed and the segment will descend, and this vibration is continued until the saw has been colnpletely ground.

Vhile the dogs It' and 7c" are used to operate the arm m the catch 763 is thrown back, as seen in Fig. 6, so as to be beyond the range of the said arm m',- but should it be necessary to impart a shorter vibrating movement to the segment G the catch k" is moved forward and serves the purpose ofa dog to reverse the movement ofthe segment while the latter is rising.

When the stone becomes worn and requires dressing an attendant gra-sps the handle t otl the spindle Q and slides the latter backward and forward in the guides S S, thereby causing the sharp teeth ot' the disks s to act on the stone and hack or dress the same.

The screw-threads of the portions of the shafts N which control the position ofthe stone are one-half the pitch of those threads of the same shaft which control the position of the dressing apparatus 5 hence as the grindstone wears away and is moved by the said screwshafts toward the segment G the dressing device is simultaneously moved, and to such an extent as to be always in a proper position for acting on the stone.

One of the most important features of my invention is the mode of adjusting the segment thereby altering the position of the segment in respect to that of the grindstone, the sawblade may be so reduced as to be thicker at the cutting-edge than at the back, and so as to be thicker near the handle than at the end.

l claim as my invention and desire to secure by Letters Patent- 1. The combination,with a grindstone, J, of a segment, G, for holding a saw-blade on its concave surface, t0 which segment a vibrating motion in the arc of a circle having a fixed center is imparted by the mechanism described, or any equivalent to the same, for the purpose specified.

2. The combination of the rock-shaft H, rods d d, segment G, and the nuts ff, or their equivalents, for adjusting the said segment on the rods.

3. The combination of the reversible pulley F, belt or band E, and segment G.

4:. The combination of the segment, its setscrew h, the sliding piece t', with its set-screw hf, and spring-lever i, the whole bein g arranged for the retention and release ofthe saw-blade, substantially as and for the purpose herein set forth.

5. rlhe combination of the segment G and its adjustable dogs 7c and 7c with the devices herein described, or the equivalent to the same, for shifting the driving-belts.

6. The grindstone-dresser composed of a number of disks,s, with pointed teeth, adapted to the sliding spindle Q', and operating substantially as and for the purpose herein set forth.

7. The screw-shafts N N, having threads of different pitches, those of one pitch controlling the position of the grindstone and those of the other pitch controlling the position of the dressing device, all substantially in the manner and for the purpose herein set forth.

In testimony whereofI have signed my name to this specification in the presence of two subscribing witnesses.

JOHN G. BAKER. Witnesses HENRY HoWsoN, JOHN WHITE. 

